Portable computer system incorporating a rear projection display

ABSTRACT

A portable computer system incorporating a rear projection display. The rear projection display is housed in a display enclosure that is movable between an open and closed position, and incorporates either a pliable or deformable projection surface or a projection surface formed of multiple rigid components. When the display enclosure is open, the projection surface is configured to expand beyond the form factor dimensions of the base portion of the portable computer. In the preferred embodiment of the invention, the projection surface is a pliable material that can be safely deformed or collapsed within the display enclosure when it is closed. The rear projection display thereby allows the effective viewing area of a portable computer display to be increased without negatively impacting the form factor dimensions or weight of the portable computer.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to displays and portable computers, andmore particularly to a portable computer system incorporating a rearprojected display apparatus to increase the effective viewing area ofthe display without negatively impacting the form factor of the portablecomputer.

[0003] 2. Description of the Related Art

[0004] Portable computers have become an everyday fixture in manypeople's personal and professional lives. Due to their mobility andversatility, portable computers are even beginning to displace desktopcomputers in many offices. Despite the fact that the average displaysize in portable computers has increased over the years, however, screensizes remain too small for many applications requiring a large viewingarea. More specifically, today's portable computers often includedisplays ranging from 10.4-inches to 12.1-inches. Many computer usersaccustomed to working with large desktop CRT monitors perceive thesesmaller portable computer displays as being inadequate.

[0005] Somewhat larger screens for portable computers have beendeveloped. However, displays cannot be made arbitrarily large. Theeffective size limit for today's display technologies is restricted bynumerous practical and technical limitations. For example, the weightadded to a portable computer by increasing its display size may beundesirable, and is often a major consideration. The form factorspecifications of a portable computer, and particularly the width andlength dimensions of the base portion, may also impose size limitationson the display. Further, problems in the manufacturing process,including problems with defects and poor yields, make larger displaysmuch more expensive to produce. These manufacturing problems areinherent and arise from basic design of traditional displays, such asthe active-matrix (AM) or thin-film-transistor (TFT) liquid crystaldisplays (LCDs).

[0006] Such displays may incorporate hundreds of thousands oftransparent transistors driving a grid of electrical traces to controloperation of liquid crystal fluid structure to generate images. As thesize and resolution of a display increases, more transistors arerequired. More transistors increases the likelihood of defects, whichoften render the display useless. Similar manufacturing problems plagueother imaging technologies, such as polymer dispersed liquid crystaldisplays (PDLCDs) and field emission displays (FEDs). As a result,display manufacturers often focus on improving image quality andreducing the power-consumption and weight of portable displays, ratherthan increasing display area.

SUMMARY OF THE INVENTION

[0007] A portable computer system according to the present inventionconsists of a base portion and a rear projection display. The rearprojection display is housed in a display enclosure that is movablebetween an open position and a closed position, and incorporates adeformable projection surface. When the display enclosure is opened, theprojection surface is configured to expand beyond the form factordimensions of the base portion of the portable computer. Preferably, theprojection surface is a pliable material that can be safely deformed orcollapsed within the projection display enclosure when closed.

[0008] In addition to the projection surface, the rear projectiondisplay is comprised of an image generator/source or display panel andan optical system for projecting an image from the image generator ontothe projection surface. When the projection display enclosure is in anopen position, its components are separated by a distance sufficient toallow proper orientation and operation of the optical system. A rearprojected display according to the invention thereby permits viewingangles and clarity comparable to that of many traditional displaytechnologies.

[0009] In one embodiment of the invention, expansion of the projectionsurface is optional, affording a smaller viewing area when the portablecomputer is operated in tight spaces. In another embodiment of theinvention, the projection surface is approximately the size of atraditional portable computer display, but the image generator ordisplay panel is smaller, lighter and less costly.

[0010] Thus, a rear projection display according to the presentinvention allows the effective viewing area of a portable computerdisplay to be increased without negatively impacting the form factordimensions, cost or weight of the portable computer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A better understanding of the present invention can be obtainedwhen the following detailed description of the preferred embodiment isconsidered in conjunction with the following drawings, in which:

[0012]FIG. 1 is a schematic block diagram of a portable computer systemincorporating a rear projection display according to the presentinvention;

[0013]FIG. 2 is an isometric view of a portable computer systemincorporating a rear projection display in accordance with the presentinvention;

[0014]FIGS. 3 and 4 are side elevation views of alternate embodiments ofa portable computer system incorporating a rear projection displayaccording to the present invention;

[0015]FIG. 5 is a front elevation view taken in cross-section of a rearprojection display utilizing a one-piece deformable projection surfaceaccording to the present invention; and

[0016]FIG. 6 is a front elevation view taken in cross-section of a rearprojection display according to the invention having a projectionsurface formed of a plurality of substantially rigid portions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0017] Turning now to the drawings, a schematic circuit diagram of aportable computer system C incorporating a rear projection display Daccording to the present invention is shown. In the preferredembodiment, the computer system C incorporates two primary buses: aPeripheral Component Interconnect (PCI) bus P which includes anaddress/data portion and a control signal portion; and an IndustryStandard Architecture (ISA) bus I which includes an address, portion, adata portion, and a control signal portion. The PCI and ISA buses P andI form the architectural backbone of the computer system C.

[0018] A CPU/memory subsystem 90 is connected to the PCI bus P. The CPU10 and a Level 2 (L2) cache 12 are connected via a processor or host busH. The CPU 10 preferably operates with a standard IBM-PC compatibleoperating system, such as Windows 95□. The L2 cache 12 provides cachingcapabilities that augment the on-chip cache of the CPU 10 to improve theoverall performance of the computer system C.

[0019] The CPU 10 and the L2 cache 12 are connected to a Host/PCI bridge14. Synchronous DRAM (SDRAM) 16 is also connected to the Host/PCI bridge14. The host/PCI bridge 14 functions to couple the CPU/memory subsystem90 to the PCI bus P. A PCMCIA/CardBus controller 18 is coupled to thePCI bus P, providing connection capabilities for a PCMCIA cards 22. ThePCMCIA cards 22 can incorporate a variety of peripheral devices,expanding the versatility of the portable computer system C.

[0020] A PCI/ISA bridge 24 is used to connect the PCI bus P and an ISAbus I. The PCI/ISA bride 24 is used to convert signals between the PCIbus P and the ISA bus I. The PCI/ISA bridge 24 includes: address anddata buffers, arbitration and bus master control logic for the PCI busP, ISA arbitration circuitry, an ISA bus controller as conventionallyused in ISA systems, an IDE (intelligent drive electronics) interface26, and a DMA controller. A hard disk drive 30 and a CD-ROM drive 28 areconnected to the IDE interface 26 of the PCI/ISA bridge 24. Tape drivesor other peripheral devices (not shown) can be similarly connected. TheIDE interface 26 is an IDE/ATA interface capable of being a busmasterand incorporating enhanced IDE features. The CD-ROM drive 28 ispreferably compliant with ATAPI (AT Attachment Packet Interface), theIDE standard for CD-ROM drives.

[0021] The PCI/ISA bridge 24 contains a set of programmable interruptcontrollers (PICs) 15 for managing hardware interrupts according totheir priority. The PICs 15 preferably include two cascaded PICs forenabling interrupts IRQO/IRQ15. In the disclosed embodiment, the PCI/ISAbridge 24 also includes miscellaneous system logic. This miscellaneoussystem logic contains counters and activity timers as conventionallypresent in personal computer systems, an interrupt controller for boththe PCI and ISA buses P and I, and power management logic. Additionally,the miscellaneous system logic may include circuitry for a securitymanagement system used for password verification and to allow access toprotected resources. Preferably, the PCI/ISA bridge 24 is a singleintegrated circuit, but other combinations are possible.

[0022] Numerous other devices are coupled to the ISA bus I. Thesedevices include a modem 32 and an audio chip 34. The audio chip 34 isfurther coupled to a device 36 for outputting analog signals, such as aset of speakers of the computer system C or an external stereo system.In the case of speakers, they are preferably configured to be audiblewhile the rear projection display D of the computer system C is in aclosed state. Also, a combination input/output (S-IO) chip 38 is coupledto the ISA bus I. The S-IO chip 38 incorporates various functions, suchas a real-time clock, UARTs, a floppy disk controller for controlling afloppy disk drive 44, various address decode logic and security logic tocontrol access to an internal or external CMOS/NVRAM memory (not shown)and stored password values. Further, the S-IO chip 38 provides aparallel port 40 and a serial port 42. To more clearly illustrate thefeatures and operation of the present invention, certain otherconventional computer devices and systems have been omitted from FIG. 1.

[0023] A keyboard controller 46 is also coupled to the ISA bus I. Thekeyboard controller 46 provides connections for a keyboard 48, a PS/2port 50 and a power switch 58. The keyboard controller 46 also generatesa data signal LCD_DATA and a clock signal LCD_CLK for use by LCD controlcircuitry 55. The LCD control circuitry 55 provides control signals forthe LCD status display 54.

[0024] The portable computer system C is capable of both receiving powerfrom and supplying power to a battery pack 64. A battery microcontroller(not shown) is incorporated in the battery pack 64 to providesupervisory functions for controlling the charging and discharging ofthe battery pack□s power cells. Preferably, the keyboard controller 46communicates with the battery microcontroller via a standard I2C-bus.The inter-integrated circuit (IC) or I2C-busis a simple bi-directionaltwo wire bus developed for efficient inter-IC control. Details of theI2C-bus can be found in □The I2C-bus and How to Use It (IncludingSpecification), □ published by Phillips Semiconductor.

[0025] A video controller circuitry 20 is also connected to the PCI busP. The video controller 20 controller circuitry incorporates videomemory and the necessary analog circuitry for controlling an imagegenerator or display panel 70 in the rear projection display D. In thedisclosed embodiment of the invention, the image generator 70 generatesimages for display on a projection surface 74. An optical system 72 isdisposed between the image generator 70 and the projection surface 74 tofocus images generated by the image generator 70 onto the projectionsurface 74. Depending on the configuration of the optical system 72, thevideo controller circuitry 20 may need to perform pre-processing stepson control signals to the image generator 70 to account for any issuesarising due to image quality and distortions.

[0026] It is contemplated that the image generator 70 could beimplemented in a variety of technologies. Such technologies includecertain liquid crystal displays (LCDs) and field emission displays(FEDs), or other display devices using emissive image generatingtechniques. Other suitable projection display technologies could also beused. Further, the optical system 72 contains optical component(s) thatare preferably constructed of a lightweight material having suitableoptical properties.

[0027] Referring now to FIG. 2, an isometric view of a portable computersystem C incorporating a rear projection display D in accordance withthe present invention is shown. The disclosed portable computer system Cincludes a base portion B pivotally coupled to the rear projectiondisplay D portion. As noted, the rear projection display D includes theimage generator 70, the optical system 72, the projection surface 74.The various components of the rear projection display D are integralwith or attached to a display enclosure 68. The display enclosure 68 ismovable between an open position (as shown in FIG. 2) and a closedposition (FIG. 5).

[0028] In the disclosed embodiments of the invention, the optical system72 is comprised of a convex lens disposed between the image generator 70and the projection surface 74 (as is seen more clearly in FIGS. 3 and4). Any such lens components of the optical system 72 are preferablyformed of a lightweight material having the necessary refraction andmagnification properties.

[0029] The projection surface 74 is attached to the display enclosure 68via a top pair of hinged or resilient attachment arms or mountingmembers 76 and a bottom pair of hinged or resilient attachment arms ormounting members 78. When the display enclosure 68 is in an openposition as shown in FIG. 2, the projection surface 74 is configured tohave an expanded surface area that exceeds the effective display area ofthe image generator 70. Preferably, the projection surface 74 is formedof a pliable material that can be safely deformed or collapsed withinthe projection display enclosure 68 when it is in a closed position. Byexpanding in this manner, the projection surface 74 allows the effectiveviewing area of the rear projection display D to exceed the viewing areaof prior displays without negatively impacting the overall size of theportable computer system C.

[0030] The top and bottom pair of hinged or resilient attachment arms ormounting members 76 and 78 are preferably spring-loaded or otherwisebiased to unfold or expand the deformable projection surface 74 when thedisplay enclosure 68 is in an open position. When the display enclosure68 is closed, a pair of retractable hooking members 80 operates to causemounting members 76 to move from an extended position and to collapsethe top portion of the projection surface 74, while a pair of rear stubs86 are utilized cause mounting members 78 to retract to facilitatecollapsing of the bottom portion of the projection surface 74. Theprojection surface 74 can also function to protect the optical system 72from abrasions when the rear projection display D is in a closedposition. It is noted that the manner of collapsing the projectionsurface 74 when the display enclosure 68 is in a closed position is notconsidered critical to the invention, and many alternate embodiments aresuitable for use with the present invention.

[0031] Referring now to FIG. 3, a side elevation view of the portablecomputer system C of FIG. 2 is shown. As more clearly illustrated, whenthe display enclosure 68 is in an open position, the various componentsof the rear projection display D are separated by distances sufficientto allow the proper orientation and operation of the optical system 72.More particularly, the distance × separating the image generator 68 andthe projection surface 74 depends to a large extent on the desired sizeof the viewing area provided by the rear projection display D, as wellas the configuration of the optical system 72. As can be appreciated,image quality may also be affected by the distance separating theoptical system 72 and the projection surface 74, and may needenhancement (e.g., a higher resolution and/or brighter image generator68) if the distance becomes too large.

[0032] The display enclosure 68 includes a bottom portion or base 84containing a connector or pivot member (not shown) used to pivotallycouple the rear projection display to the base portion B of the portablecomputer system C. In addition to providing support for the remainingportions of the display enclosure 68 and the integral image generator70, the base 84 of the display enclosure 68 also includes attachmentpoints 82 for rigidly supporting the lens of the optical system 72. Anoptional polarizing filter (not illustrated) may also be disposed eitherbetween the image generator 70 and the optical system 72 or between theoptical system 72 and the projection surface 74. The polarizing filtermay improve the image quality of the rear projection display undercertain ambient conditions.

[0033] It is also contemplated that the projection surface 74 can beoptionally configured to collapse when the display enclosure 68 is inthe opened position, thereby affording a smaller viewing area when theportable computer system C is operated in tight spaces that do notpermit an increased viewing area. Further, it is contemplated that theimage generator 70, the optical system 72 and the projection surface 74can be reduced in size such that the viewing area provided by theprojection surface 74 is comparable to that of existing portablecomputer displays. This embodiment of the invention has the advantage ofallowing use of a smaller image generator 70, which may function toreduce both overall cost and weight of the portable computer system C.

[0034] Referring now to FIG. 4, a side elevation view of an alternateembodiment of a rear projection display according to the presentinvention is shown. In this embodiment of the invention, the retractablehooking members 80 and rear stubs 86 are replaced by a roller assemblycomprised of the guide roller 90 and a primary roller 92. The guideroller 90 is secured to the base portion B via a pin 94, while theprimary roller 92 is secured to the base portion B via a pin 96. Theprimary roller 92 is preferably spring-loaded, such that it stores aretractable spool or portion of the projection surface 74 when thedisplay enclosure 68 is in a closed position. Preferably, the springtension of the primary roller 92 can be selectively applied such thatclosure of the display enclosure 68 activates the primary roller 92 in amanner sufficient to overcome the tension provided by the top pair ofhinged or resilient attachment members 76. The tension provided by theprimary roller 92 can be relaxed when the display enclosure 68 is movedto an open position as shown in FIG. 4, such that the tension providedby the top pair of hinged or resilient attachment members 76 issufficient to expand the projection surface 74 into an extended or tautposition. Again, many other mechanical apparatus for expanding andretracting the deformable projection surface 74 are suitable for usewith the present invention.

[0035] Referring now to FIG. 5, a front elevation view taken incross-section of a rear projection display utilizing a one-piecedeformable projection surface 74 in accordance with the presentinvention is shown. In this embodiment of the invention, the projectionsurface 74 is shown in a compressed (i.e., the rear projection display Dis in a closed state). The projection surface 74 roughly conforms to thecontour of the base portion B of the portable computer system C viapressure applied by the hinged or resilient attachment members 76 (and78). Alternatively, the projection surface 74 could be expanded andcontracted manually.

[0036] Referring now to FIG. 6, front elevation view taken incross-section of another embodiment of a rear projection displayaccording to the present invention is shown. In this embodiment of theinvention, the projection surface is formed of a substantially rigidmain display panel 100, as well as two substantially rigid ancillarydisplay panels 102. The ancillary panels 102 are connected to the maindisplay panel by hinges 104. The ancillary display panels 102 are shownin a folded or collapsed state, and are rotatable about hinges 104 tobecome substantially co-planar with the main display panel 100, therebyforming a larger display area when the rear projection display D is inan opened state. The hinges 104 may be spring-loaded, or may operatemanually. Preferably, the hinge(s) 104 attaching an individual one ofthe ancillary display panels 102 are located near the top and bottomedges of the ancillary display panels 102 such that they do notsubstantially impair the images provided on the display panels 100 and102.

[0037] Further, in order to maintain proper spacing between the variouscomponents of the rear projection display D of FIG. 6, the displayenclosure 68 may incorporate compressible portions 106 which attach tothe main display panel 100 at its top and/or bottom edges. Thecompressible portions 106 function to extend the main display panel 100and the ancillary display panels 102 away from the optical system 72when the rear projection display D is in an open and operable position.

[0038] As evident from the foregoing, a portable computer system displayaccording to the present invention may take the form of variousembodiments of a rear projection display. The rear projection display ishoused in a display enclosure that is movable between an open and closedposition, and incorporates either a pliable or deformable projectionsurface or a projection surface formed of multiple rigid components.When the display enclosure is open, the projection surface is configuredto expand beyond the form factor dimensions of the base portion of theportable computer. In the preferred embodiment of the invention, theprojection surface is a pliable material that can be safely deformed orcollapsed within the display enclosure when it is closed.

[0039] The foregoing disclosure and description of the invention areillustrative and explanatory thereof, and various changes in the size,shape, materials, components, circuit elements, wiring connections andcontacts, as well as in the details of the illustrated circuitry andconstruction and method of operation may be made without departing fromthe spirit of the invention.

1. A portable computer system, comprising: a base portion having a topsurface; and a projection display coupled to the base portion andmovable between an open position and a closed position with respect tothe base portion, the projection display comprising: an image generatorfor generating images; a projection surface for displaying imagesgenerated by the image generator; and an optical system disposed betweenthe image generator and the projection surface, the optical systemconfigured to discernably focus images generated by the image generatoronto the projection surface.
 2. The portable computer system of claim 1, wherein the projection surface is formed of a pliable material, thepliable material capable of being expanded to have a surface areagreater than the display area of the image generator when the projectiondisplay is in an open position.
 3. The portable computer system of claim1 , wherein the projection surface is formed of a plurality of rigidpanels.
 4. The portable computer system of claim 3 , wherein the rigidpanels comprise a main display panel and two ancilliary display panels,the two ancilliary display panels coupled to the main display panel andmovable with respect to the main display panel between a folded positionand a substantially coplanar position.
 5. The portable computer systemof claim 4 , further comprising: a display enclosure, the imagegenerator and optical system being integral with or rigidly coupled tothe display enclosure; and resilient attachment members, wherein theprojection surface is attached to the display enclosure via theresilient attachment members.
 6. The portable computer system of claim 5, further comprising: a display enclosure, the image generator andoptical system being integral with or rigidly coupled to the displayenclosure; and hinged attachment members, wherein the projection surfaceis attached to the display enclosure via the hinged attachment members.7. The portable computer system of claim 1 , further comprising meansfor collapsing the projection surface when the projection display ismoved to a closed position.
 8. The portable computer system of claim 7 ,wherein the means for collapsing the projection surface compriseretractable hooking members.
 9. The portable computer system of claim 7, wherein the means for collapsing the projection surface comprise aroller assembly.
 10. The portable computer system of claim 1 , furthercomprising a polarizing filter disposed between the image generator andthe projection surface.
 11. The portable computer system of claim 1 ,wherein the image generator is a field emission display.
 12. Theportable computer system of claim 1 , wherein the image generator is aliquid crystal display.
 13. The portable computer system of claim 1 ,wherein the optical system is a convex lens.
 14. A projection displayfor attachment to a base portion of a portable computer system, theprojection display comprising: an image generator for generating images;a projection surface for displaying images generated by the imagegenerator; and an optical system disposed between the image generatorand the projection surface, the optical system configured to discernablyfocus images generated by the image generator onto the projectionsurface.
 15. The projection display of claim 14 , wherein the projectionsurface is formed of a pliable material, the pliable material, whentaut, having a surface area greater than the display area of the imagegenerator.
 16. The projection display of claim 14 , wherein theprojection surface is formed of a plurality of rigid panels.
 17. Theprojection display of claim 16 , wherein the rigid panels comprise amain display panel and two ancilliary display panels, the two ancilliarydisplay panels coupled to the main display panel and movable withrespect to the main display panel between a folded position and asubstantially coplanar position.
 18. The projection display of claim 14, wherein the image generator is a field emission display.
 19. Theprojection display of claim 14 , wherein the image generator is a liquidcrystal display.
 20. The projection display of claim 14 , wherein theoptical system is a convex lens.